| Message ID | 20200429014248.893731-1-kuba@kernel.org |
|---|---|
| State | Changes Requested |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net-next] devlink: let kernel allocate region snapshot id | expand |
Wed, Apr 29, 2020 at 03:42:48AM CEST, kuba@kernel.org wrote: >Currently users have to choose a free snapshot id before >calling DEVLINK_CMD_REGION_NEW. This is potentially racy >and inconvenient. > >Make the DEVLINK_ATTR_REGION_SNAPSHOT_ID optional and try >to allocate id automatically. Send a message back to the >caller with the snapshot info. > >The message carrying id gets sent immediately, but the >allocation is only valid if the entire operation succeeded. >This makes life easier, as sending the notification itself >may fail. > >Example use: >$ devlink region new netdevsim/netdevsim1/dummy >netdevsim/netdevsim1/dummy: snapshot 1 > >$ id=$(devlink -j region new netdevsim/netdevsim1/dummy | \ > jq '.[][][][]') >$ devlink region dump netdevsim/netdevsim1/dummy snapshot $id >[...] >$ devlink region del netdevsim/netdevsim1/dummy snapshot $id > >Signed-off-by: Jakub Kicinski <kuba@kernel.org> >--- >Jiri, this is what I had in mind of snapshots and the same >thing will come back for slice allocation. Okay. Could you please send the userspace patch too in order to see the full picture? > > net/core/devlink.c | 84 ++++++++++++++++--- > .../drivers/net/netdevsim/devlink.sh | 13 +++ > 2 files changed, 84 insertions(+), 13 deletions(-) > >diff --git a/net/core/devlink.c b/net/core/devlink.c >index 1ec2e9fd8898..dad5d07dd4f8 100644 >--- a/net/core/devlink.c >+++ b/net/core/devlink.c >@@ -4065,10 +4065,65 @@ static int devlink_nl_cmd_region_del(struct sk_buff *skb, > return 0; > } > >+static int >+devlink_nl_alloc_snapshot_id(struct devlink *devlink, struct genl_info *info, >+ struct devlink_region *region, u32 *snapshot_id) >+{ >+ struct sk_buff *msg; >+ void *hdr; >+ int err; >+ >+ err = __devlink_region_snapshot_id_get(devlink, snapshot_id); >+ if (err) { >+ NL_SET_ERR_MSG_MOD(info->extack, No need to wrap here. >+ "Failed to allocate a new snapshot id"); >+ return err; >+ } >+ >+ msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); >+ if (!msg) { >+ err = -ENOMEM; >+ goto err_msg_alloc; >+ } >+ >+ hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, >+ &devlink_nl_family, 0, DEVLINK_CMD_REGION_NEW); >+ if (!hdr) { >+ err = -EMSGSIZE; >+ goto err_put_failure; >+ } >+ err = devlink_nl_put_handle(msg, devlink); >+ if (err) >+ goto err_attr_failure; >+ err = nla_put_string(msg, DEVLINK_ATTR_REGION_NAME, region->ops->name); >+ if (err) >+ goto err_attr_failure; >+ err = nla_put_u32(msg, DEVLINK_ATTR_REGION_SNAPSHOT_ID, *snapshot_id); >+ if (err) >+ goto err_attr_failure; >+ genlmsg_end(msg, hdr); >+ >+ err = genlmsg_reply(msg, info); >+ if (err) >+ goto err_reply; >+ >+ return 0; >+ >+err_attr_failure: >+ genlmsg_cancel(msg, hdr); >+err_put_failure: >+ nlmsg_free(msg); >+err_msg_alloc: >+err_reply: >+ __devlink_snapshot_id_decrement(devlink, *snapshot_id); >+ return err; >+} >+ > static int > devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info) > { > struct devlink *devlink = info->user_ptr[0]; >+ struct nlattr *snapshot_id_attr; > struct devlink_region *region; > const char *region_name; > u32 snapshot_id; >@@ -4080,11 +4135,6 @@ devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info) > return -EINVAL; > } > >- if (!info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]) { >- NL_SET_ERR_MSG_MOD(info->extack, "No snapshot id provided"); >- return -EINVAL; >- } >- > region_name = nla_data(info->attrs[DEVLINK_ATTR_REGION_NAME]); > region = devlink_region_get_by_name(devlink, region_name); > if (!region) { >@@ -4102,16 +4152,24 @@ devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info) > return -ENOSPC; > } > >- snapshot_id = nla_get_u32(info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]); >+ snapshot_id_attr = info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]; >+ if (snapshot_id_attr) { >+ snapshot_id = nla_get_u32(snapshot_id_attr); > >- if (devlink_region_snapshot_get_by_id(region, snapshot_id)) { >- NL_SET_ERR_MSG_MOD(info->extack, "The requested snapshot id is already in use"); >- return -EEXIST; >- } >+ if (devlink_region_snapshot_get_by_id(region, snapshot_id)) { >+ NL_SET_ERR_MSG_MOD(info->extack, "The requested snapshot id is already in use"); >+ return -EEXIST; >+ } > >- err = __devlink_snapshot_id_insert(devlink, snapshot_id); >- if (err) >- return err; >+ err = __devlink_snapshot_id_insert(devlink, snapshot_id); >+ if (err) >+ return err; >+ } else { >+ err = devlink_nl_alloc_snapshot_id(devlink, info, >+ region, &snapshot_id); >+ if (err) >+ return err; >+ } > > err = region->ops->snapshot(devlink, info->extack, &data); How the output is going to looks like it this or any of the follow-up calls in this function are going to fail? I guess it is going to be handled gracefully in the userspace app, right? > if (err) >diff --git a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh >index 9f9741444549..ad539eccddcb 100755 >--- a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh >+++ b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh >@@ -151,6 +151,19 @@ regions_test() > > check_region_snapshot_count dummy post-second-delete 2 > >+ sid=$(devlink -j region new $DL_HANDLE/dummy | jq '.[][][][]') >+ check_err $? "Failed to create a new snapshot with id allocated by the kernel" >+ >+ check_region_snapshot_count dummy post-first-request 3 >+ >+ devlink region dump $DL_HANDLE/dummy snapshot $sid >> /dev/null >+ check_err $? "Failed to dump a snapshot with id allocated by the kernel" >+ >+ devlink region del $DL_HANDLE/dummy snapshot $sid >+ check_err $? "Failed to delete snapshot with id allocated by the kernel" >+ >+ check_region_snapshot_count dummy post-first-request 2 >+ > log_test "regions test" > } > >-- >2.25.4 >
> -----Original Message----- > From: netdev-owner@vger.kernel.org <netdev-owner@vger.kernel.org> On > Behalf Of Jiri Pirko > Sent: Tuesday, April 28, 2020 10:46 PM > To: Jakub Kicinski <kuba@kernel.org> > Cc: davem@davemloft.net; netdev@vger.kernel.org; kernel-team@fb.com; > Keller, Jacob E <jacob.e.keller@intel.com> > Subject: Re: [PATCH net-next] devlink: let kernel allocate region snapshot id > > Wed, Apr 29, 2020 at 03:42:48AM CEST, kuba@kernel.org wrote: > >Currently users have to choose a free snapshot id before > >calling DEVLINK_CMD_REGION_NEW. This is potentially racy > >and inconvenient. > > I did propose something like this originally, but.... > >Make the DEVLINK_ATTR_REGION_SNAPSHOT_ID optional and try > >to allocate id automatically. Send a message back to the > >caller with the snapshot info. > > ... sending a message back makes this work better. > >The message carrying id gets sent immediately, but the > >allocation is only valid if the entire operation succeeded. > >This makes life easier, as sending the notification itself > >may fail. > > It seems like we could wait until at least after the region is captured. > >Example use: > >$ devlink region new netdevsim/netdevsim1/dummy > >netdevsim/netdevsim1/dummy: snapshot 1 > > > >$ id=$(devlink -j region new netdevsim/netdevsim1/dummy | \ > > jq '.[][][][]') > >$ devlink region dump netdevsim/netdevsim1/dummy snapshot $id > >[...] > >$ devlink region del netdevsim/netdevsim1/dummy snapshot $id > > > >Signed-off-by: Jakub Kicinski <kuba@kernel.org> > >--- > >Jiri, this is what I had in mind of snapshots and the same > >thing will come back for slice allocation. > > Okay. Could you please send the userspace patch too in order to see the > full picture? > Yes, I'd like to see this as well. > > > > > net/core/devlink.c | 84 ++++++++++++++++--- > > .../drivers/net/netdevsim/devlink.sh | 13 +++ > > 2 files changed, 84 insertions(+), 13 deletions(-) > > > >diff --git a/net/core/devlink.c b/net/core/devlink.c > >index 1ec2e9fd8898..dad5d07dd4f8 100644 > >--- a/net/core/devlink.c > >+++ b/net/core/devlink.c > >@@ -4065,10 +4065,65 @@ static int devlink_nl_cmd_region_del(struct sk_buff > *skb, > > return 0; > > } > > > >+static int > >+devlink_nl_alloc_snapshot_id(struct devlink *devlink, struct genl_info *info, > >+ struct devlink_region *region, u32 *snapshot_id) > >+{ > >+ struct sk_buff *msg; > >+ void *hdr; > >+ int err; > >+ > >+ err = __devlink_region_snapshot_id_get(devlink, snapshot_id); > >+ if (err) { > >+ NL_SET_ERR_MSG_MOD(info->extack, > > No need to wrap here. > > > >+ "Failed to allocate a new snapshot id"); > >+ return err; > >+ } > >+ > >+ msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); > >+ if (!msg) { > >+ err = -ENOMEM; > >+ goto err_msg_alloc; > >+ } > >+ > >+ hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, > >+ &devlink_nl_family, 0, DEVLINK_CMD_REGION_NEW); > >+ if (!hdr) { > >+ err = -EMSGSIZE; > >+ goto err_put_failure; > >+ } > >+ err = devlink_nl_put_handle(msg, devlink); > >+ if (err) > >+ goto err_attr_failure; > >+ err = nla_put_string(msg, DEVLINK_ATTR_REGION_NAME, region->ops- > >name); > >+ if (err) > >+ goto err_attr_failure; > >+ err = nla_put_u32(msg, DEVLINK_ATTR_REGION_SNAPSHOT_ID, > *snapshot_id); > >+ if (err) > >+ goto err_attr_failure; > >+ genlmsg_end(msg, hdr); > >+ > >+ err = genlmsg_reply(msg, info); > >+ if (err) > >+ goto err_reply; > >+ > >+ return 0; > >+ > >+err_attr_failure: > >+ genlmsg_cancel(msg, hdr); > >+err_put_failure: > >+ nlmsg_free(msg); > >+err_msg_alloc: > >+err_reply: > >+ __devlink_snapshot_id_decrement(devlink, *snapshot_id); > >+ return err; > >+} > >+ > > static int > > devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info) > > { > > struct devlink *devlink = info->user_ptr[0]; > >+ struct nlattr *snapshot_id_attr; > > struct devlink_region *region; > > const char *region_name; > > u32 snapshot_id; > >@@ -4080,11 +4135,6 @@ devlink_nl_cmd_region_new(struct sk_buff *skb, > struct genl_info *info) > > return -EINVAL; > > } > > > >- if (!info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]) { > >- NL_SET_ERR_MSG_MOD(info->extack, "No snapshot id > provided"); > >- return -EINVAL; > >- } > >- > > region_name = nla_data(info->attrs[DEVLINK_ATTR_REGION_NAME]); > > region = devlink_region_get_by_name(devlink, region_name); > > if (!region) { > >@@ -4102,16 +4152,24 @@ devlink_nl_cmd_region_new(struct sk_buff *skb, > struct genl_info *info) > > return -ENOSPC; > > } > > > >- snapshot_id = nla_get_u32(info- > >attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]); > >+ snapshot_id_attr = info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]; > >+ if (snapshot_id_attr) { > >+ snapshot_id = nla_get_u32(snapshot_id_attr); > > > >- if (devlink_region_snapshot_get_by_id(region, snapshot_id)) { > >- NL_SET_ERR_MSG_MOD(info->extack, "The requested snapshot > id is already in use"); > >- return -EEXIST; > >- } > >+ if (devlink_region_snapshot_get_by_id(region, snapshot_id)) { > >+ NL_SET_ERR_MSG_MOD(info->extack, "The requested > snapshot id is already in use"); > >+ return -EEXIST; > >+ } > > > >- err = __devlink_snapshot_id_insert(devlink, snapshot_id); > >- if (err) > >- return err; > >+ err = __devlink_snapshot_id_insert(devlink, snapshot_id); > >+ if (err) > >+ return err; > >+ } else { > >+ err = devlink_nl_alloc_snapshot_id(devlink, info, > >+ region, &snapshot_id); > >+ if (err) > >+ return err; > >+ } > > > > err = region->ops->snapshot(devlink, info->extack, &data); > > How the output is going to looks like it this or any of the follow-up > calls in this function are going to fail? > > I guess it is going to be handled gracefully in the userspace app, > right? > > I'm wondering what the issue is with just waiting to send the snapshot id back until after this succeeds. Is it just easier to keep it near the allocation? Thanks, Jake
On Wed, 29 Apr 2020 07:45:52 +0200 Jiri Pirko wrote: > Wed, Apr 29, 2020 at 03:42:48AM CEST, kuba@kernel.org wrote: > >Jiri, this is what I had in mind of snapshots and the same > >thing will come back for slice allocation. > > Okay. Could you please send the userspace patch too in order to see the > full picture? You got it, I didn't do anything fancy there. > >+static int > >+devlink_nl_alloc_snapshot_id(struct devlink *devlink, struct genl_info *info, > >+ struct devlink_region *region, u32 *snapshot_id) > >+{ > >+ struct sk_buff *msg; > >+ void *hdr; > >+ int err; > >+ > >+ err = __devlink_region_snapshot_id_get(devlink, snapshot_id); > >+ if (err) { > >+ NL_SET_ERR_MSG_MOD(info->extack, > > No need to wrap here. Ok. > >+ "Failed to allocate a new snapshot id"); > >+ return err; > >+ } > >- err = __devlink_snapshot_id_insert(devlink, snapshot_id); > >- if (err) > >- return err; > >+ err = __devlink_snapshot_id_insert(devlink, snapshot_id); > >+ if (err) > >+ return err; > >+ } else { > >+ err = devlink_nl_alloc_snapshot_id(devlink, info, > >+ region, &snapshot_id); > >+ if (err) > >+ return err; > >+ } > > > > err = region->ops->snapshot(devlink, info->extack, &data); > > How the output is going to looks like it this or any of the follow-up > calls in this function are going to fail? > > I guess it is going to be handled gracefully in the userspace app, > right? The output is the same, just the return code is non-zero. I can change that not to print the snapshot info until we are sure the operation succeeded if you prefer. Initially I had the kernel not sent the message until it's done with the operation, but that seems unnecessarily complex. The send operation itself may fail, and if we ever have an operation that requires more than one notification we'll have to struggle with atomic sends. Better have the user space treat the failure like an exception, and ignore all the notifications that came earlier. That said the iproute2 patch can be improved with extra 20 lines so that it holds off printing the snapshot info until success.
On Wed, 29 Apr 2020 15:34:30 +0000 Keller, Jacob E wrote: > > How the output is going to looks like it this or any of the follow-up > > calls in this function are going to fail? > > > > I guess it is going to be handled gracefully in the userspace app, > > right? > > I'm wondering what the issue is with just waiting to send the > snapshot id back until after this succeeds. Is it just easier to keep > it near the allocation? I just wasn't happy with the fact that the response send may fail. So it just seems like better protocol from the start to expect user space to pay attention to the error code at the end, before it takes action on the response.
> -----Original Message----- > From: Jakub Kicinski <kuba@kernel.org> > Sent: Wednesday, April 29, 2020 9:39 AM > To: Keller, Jacob E <jacob.e.keller@intel.com> > Cc: Jiri Pirko <jiri@resnulli.us>; davem@davemloft.net; netdev@vger.kernel.org; > kernel-team@fb.com > Subject: Re: [PATCH net-next] devlink: let kernel allocate region snapshot id > > On Wed, 29 Apr 2020 15:34:30 +0000 Keller, Jacob E wrote: > > > How the output is going to looks like it this or any of the follow-up > > > calls in this function are going to fail? > > > > > > I guess it is going to be handled gracefully in the userspace app, > > > right? > > > > I'm wondering what the issue is with just waiting to send the > > snapshot id back until after this succeeds. Is it just easier to keep > > it near the allocation? > > I just wasn't happy with the fact that the response send may fail. > So it just seems like better protocol from the start to expect user > space to pay attention to the error code at the end, before it takes > action on the response. Ok that seems reasonable to me. Can we get documentation updates for this? Thanks, Jake
Wed, Apr 29, 2020 at 06:35:18PM CEST, kuba@kernel.org wrote: >On Wed, 29 Apr 2020 07:45:52 +0200 Jiri Pirko wrote: >> Wed, Apr 29, 2020 at 03:42:48AM CEST, kuba@kernel.org wrote: >> >Jiri, this is what I had in mind of snapshots and the same >> >thing will come back for slice allocation. >> >> Okay. Could you please send the userspace patch too in order to see the >> full picture? > >You got it, I didn't do anything fancy there. > >> >+static int >> >+devlink_nl_alloc_snapshot_id(struct devlink *devlink, struct genl_info *info, >> >+ struct devlink_region *region, u32 *snapshot_id) >> >+{ >> >+ struct sk_buff *msg; >> >+ void *hdr; >> >+ int err; >> >+ >> >+ err = __devlink_region_snapshot_id_get(devlink, snapshot_id); >> >+ if (err) { >> >+ NL_SET_ERR_MSG_MOD(info->extack, >> >> No need to wrap here. > >Ok. > >> >+ "Failed to allocate a new snapshot id"); >> >+ return err; >> >+ } > >> >- err = __devlink_snapshot_id_insert(devlink, snapshot_id); >> >- if (err) >> >- return err; >> >+ err = __devlink_snapshot_id_insert(devlink, snapshot_id); >> >+ if (err) >> >+ return err; >> >+ } else { >> >+ err = devlink_nl_alloc_snapshot_id(devlink, info, >> >+ region, &snapshot_id); >> >+ if (err) >> >+ return err; >> >+ } >> > >> > err = region->ops->snapshot(devlink, info->extack, &data); >> >> How the output is going to looks like it this or any of the follow-up >> calls in this function are going to fail? >> >> I guess it is going to be handled gracefully in the userspace app, >> right? > >The output is the same, just the return code is non-zero. > >I can change that not to print the snapshot info until we are sure the >operation succeeded if you prefer. I think that would be clean to do this, in kernel. > >Initially I had the kernel not sent the message until it's done with >the operation, but that seems unnecessarily complex. The send operation >itself may fail, and if we ever have an operation that requires more >than one notification we'll have to struggle with atomic sends. > >Better have the user space treat the failure like an exception, and >ignore all the notifications that came earlier. > >That said the iproute2 patch can be improved with extra 20 lines so >that it holds off printing the snapshot info until success.
diff --git a/net/core/devlink.c b/net/core/devlink.c index 1ec2e9fd8898..dad5d07dd4f8 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -4065,10 +4065,65 @@ static int devlink_nl_cmd_region_del(struct sk_buff *skb, return 0; } +static int +devlink_nl_alloc_snapshot_id(struct devlink *devlink, struct genl_info *info, + struct devlink_region *region, u32 *snapshot_id) +{ + struct sk_buff *msg; + void *hdr; + int err; + + err = __devlink_region_snapshot_id_get(devlink, snapshot_id); + if (err) { + NL_SET_ERR_MSG_MOD(info->extack, + "Failed to allocate a new snapshot id"); + return err; + } + + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL); + if (!msg) { + err = -ENOMEM; + goto err_msg_alloc; + } + + hdr = genlmsg_put(msg, info->snd_portid, info->snd_seq, + &devlink_nl_family, 0, DEVLINK_CMD_REGION_NEW); + if (!hdr) { + err = -EMSGSIZE; + goto err_put_failure; + } + err = devlink_nl_put_handle(msg, devlink); + if (err) + goto err_attr_failure; + err = nla_put_string(msg, DEVLINK_ATTR_REGION_NAME, region->ops->name); + if (err) + goto err_attr_failure; + err = nla_put_u32(msg, DEVLINK_ATTR_REGION_SNAPSHOT_ID, *snapshot_id); + if (err) + goto err_attr_failure; + genlmsg_end(msg, hdr); + + err = genlmsg_reply(msg, info); + if (err) + goto err_reply; + + return 0; + +err_attr_failure: + genlmsg_cancel(msg, hdr); +err_put_failure: + nlmsg_free(msg); +err_msg_alloc: +err_reply: + __devlink_snapshot_id_decrement(devlink, *snapshot_id); + return err; +} + static int devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info) { struct devlink *devlink = info->user_ptr[0]; + struct nlattr *snapshot_id_attr; struct devlink_region *region; const char *region_name; u32 snapshot_id; @@ -4080,11 +4135,6 @@ devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info) return -EINVAL; } - if (!info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]) { - NL_SET_ERR_MSG_MOD(info->extack, "No snapshot id provided"); - return -EINVAL; - } - region_name = nla_data(info->attrs[DEVLINK_ATTR_REGION_NAME]); region = devlink_region_get_by_name(devlink, region_name); if (!region) { @@ -4102,16 +4152,24 @@ devlink_nl_cmd_region_new(struct sk_buff *skb, struct genl_info *info) return -ENOSPC; } - snapshot_id = nla_get_u32(info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]); + snapshot_id_attr = info->attrs[DEVLINK_ATTR_REGION_SNAPSHOT_ID]; + if (snapshot_id_attr) { + snapshot_id = nla_get_u32(snapshot_id_attr); - if (devlink_region_snapshot_get_by_id(region, snapshot_id)) { - NL_SET_ERR_MSG_MOD(info->extack, "The requested snapshot id is already in use"); - return -EEXIST; - } + if (devlink_region_snapshot_get_by_id(region, snapshot_id)) { + NL_SET_ERR_MSG_MOD(info->extack, "The requested snapshot id is already in use"); + return -EEXIST; + } - err = __devlink_snapshot_id_insert(devlink, snapshot_id); - if (err) - return err; + err = __devlink_snapshot_id_insert(devlink, snapshot_id); + if (err) + return err; + } else { + err = devlink_nl_alloc_snapshot_id(devlink, info, + region, &snapshot_id); + if (err) + return err; + } err = region->ops->snapshot(devlink, info->extack, &data); if (err) diff --git a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh index 9f9741444549..ad539eccddcb 100755 --- a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh +++ b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh @@ -151,6 +151,19 @@ regions_test() check_region_snapshot_count dummy post-second-delete 2 + sid=$(devlink -j region new $DL_HANDLE/dummy | jq '.[][][][]') + check_err $? "Failed to create a new snapshot with id allocated by the kernel" + + check_region_snapshot_count dummy post-first-request 3 + + devlink region dump $DL_HANDLE/dummy snapshot $sid >> /dev/null + check_err $? "Failed to dump a snapshot with id allocated by the kernel" + + devlink region del $DL_HANDLE/dummy snapshot $sid + check_err $? "Failed to delete snapshot with id allocated by the kernel" + + check_region_snapshot_count dummy post-first-request 2 + log_test "regions test" }
Currently users have to choose a free snapshot id before calling DEVLINK_CMD_REGION_NEW. This is potentially racy and inconvenient. Make the DEVLINK_ATTR_REGION_SNAPSHOT_ID optional and try to allocate id automatically. Send a message back to the caller with the snapshot info. The message carrying id gets sent immediately, but the allocation is only valid if the entire operation succeeded. This makes life easier, as sending the notification itself may fail. Example use: $ devlink region new netdevsim/netdevsim1/dummy netdevsim/netdevsim1/dummy: snapshot 1 $ id=$(devlink -j region new netdevsim/netdevsim1/dummy | \ jq '.[][][][]') $ devlink region dump netdevsim/netdevsim1/dummy snapshot $id [...] $ devlink region del netdevsim/netdevsim1/dummy snapshot $id Signed-off-by: Jakub Kicinski <kuba@kernel.org> --- Jiri, this is what I had in mind of snapshots and the same thing will come back for slice allocation. net/core/devlink.c | 84 ++++++++++++++++--- .../drivers/net/netdevsim/devlink.sh | 13 +++ 2 files changed, 84 insertions(+), 13 deletions(-)